Valve for rock drills



July 7, 1931. w. A. SMITH. JR I 1,813,773

VALVE FOR ROCK DRILLS Filed Aug. 14, 1928 J 1' Z. "fd f j F12. -1. B A E0 IN VEN TOR.

A IfillianzZI-Jmi 671/ 271 7.

H15 ATTORNEY.

Patented July 7, 1931 iii; STATES WILLIAM: A. SMITH, JR., FPHILLIPSIBURG, NEW JERSEY, ASSIGNOR TO INGERSOLL- I BAND COMPANY, OFJERSEY CITY, NEW JERSEY, A CORPORATION OF NEXV JERSEY VALVE FOR ROCKDRILLS Application filed August 14, 1928. Serial No. 299,492.

This invention relates to rock drills, but more particularly to adistributing valve for fluid actuated rock drills of the hammer type.

The objects of the invention are to obtain p a durable and light weightvalve capable of a rapid and positive action for distributing thepressure fluid to the ends of the cylinder.

.Other objects will be in part obvious and in part pointed outhereinafter, and to all of these ends the invention consists of thecombination of elements, features of construction and arrangement ofparts substantially as hereinafter described and claimed and illustratedin the accompanying drawings, in which Figure 1 is a longitudinalsectional elevation of a portion of a rock drill showing the valve inposition for admitting pressure fluid into the rearward end of thecylinder,

and

o an extension E of the piston B.

The rearward end of the cylinder A is suitably recessed to receive aback cylinder washer F which acts as a closure for the rearward end ofthe cylinder and in this instance 3 also acts as a seat for a back headG which may be secured to the cylinder by means of suitable side rods H,only a portion of one of which is shown. I

-The rock drill is provided with a valve chest J disposed in thisinstance on the side of the cylinder A and having a bore K to form avalve chamber. In the rearward end of the valve chest J is a throttlevalve chamber L in which is disposed a throttle valve 0 whereby theadmission of pressure fluid from a suitable source of supply to the boreK is controlled. For this purpose the throttle valve O is provided witha lever P.

The throttle valve illustrated has a central chamber Q, which may beconstantly exposed the valve chest leading to the end of the v bore K.

Disposed in the innermost end of the bore K is a bushing T which may besecured in the bore K in any suitable manner and has a. passage U inconstant communication with the passage S in the valve chest J. In theopposite or open end V of the valve chest J is a somewhat similarbushing W which forms a closure for the open end of the bore K. Thebushing W has an integral flange X which abuts the end of the valvechest J and through which may extend securing means such as bolts Ywhereby the bushing W is secured to the valve chest J.

v The bushings T and W are provided with suitable bores Z and brespectively which form reduced portions of the valve chamber. Thebushings T and W in this instance are suitably spaced to form anintermediate enlarged portion 0 of the valve chamber.

The distribution of pressure fluid to the ends of the cylinder iseffected by a distributing valve d having a longitudinal bore 6extending entirely therethrough. The bore c is constantly exposed tolive pressure fluid which flows from the throttle valve 0 into thedistributing valve d through the passages S and U and the port R. Thevalve 0? is provided with a pair of flanges f and g which are slidablydisposed in the enlarged portion 0 of the valve chamber.

Leading from the rearward end of the reduced portion Z to thecorresponding end of the cylinder A is an inlet passage 72, throughwhich pressure fluid may flow for impelling the piston B in a forwardlydirection. Similarly at the front end of the reduced portion Z-is aninlet passage 7' which leads to the front end of the cylinder. Portionsof the passagesh and j in this instance serve both as inlet and exhaustpassages and in this instance exhaust passages 70 and 0 lead from thepassages h and respectively to the enlarged portion 0 of the valvechamber. The passages 70 and 0 are so disposed that they may be coveredby the flanges f and g of the valve for controlling the exhaust ofpressure fluid from the ends of the cylinder into the intermediateportion 0 of the valve chamber from whence such fluid may escape to theatmosphere through an exhaust port p in the valve chest, said exhaustport p being centrally located in the valve chamber.

The outermost ends g and r of the flange and g respectively constituteactuating surfaces against which pressure fluid may act for actuatingthe valve. Such pressure fluid in this instance is conveyed from thecylinder through kicker passages s and t. The kicker passages s and tare crossed in this instance, the passage 8 leading from a pointforwardly of the inlet passage h to the front end of the enlargedportion 0 of the valve chamber, and the passage t leading from a pointrearwardly of the inlet passage 7' to the rearward end of the enlargedportion 0 of the valve chamber. Vents a formed in the valve chest nearthe ends of the enlarged portion 0 afford passages for the escape of aportion of the pressure fluid used to actuate the valve and arecontrolled by the flanges f and g.

In the construction shown the ends of the valve cl constitute holdingsurfaces. Accordingly a holding surface 1) is formed on the rearward endof the valve and is adapted to cooperate or seat against a surface w inthe bushing T for cutting off the supply of pressure fluid to therearward end of the cylinder. In like manner the front end of the valveis provided with a holding surface 06 against which pressure fluid mayact for holding the valve (Z in a rearwardly position and said holdingsurface w is adapted to seat against a surface y in the bushing V to cutoff the supply of pressure fluid to the front end of the cylinder.

lhe operation of the device is as follows: With the valve (5 and thepiston B in the positions shown in Figure 1, pressure fluid entering thebore 6 of the valve will flow over the rearward end of the valve and actagainst the holding surface i) to hold the valve (Z forwardly and thenceflows through the inlet passage 7t into the rearward end of the cylinderto actuate the piston B forwardly against the implement intended to beactuated. In this position of the valve the flange f will cover theoutlet opening of the exhaust passage is so that there will he no lossof pressure fluid through this passage.

As the piston B proceeds forwardly the kicker passage 8 will beuncovered thereby and pressure fluid will then flow through said kickerpassage into the front end of the enlarged portion 0. This pressurefluid will act against the actuating surface 1 of the flange g and willthrow the valve (Z rearwardly to the position illustrated in Figure 2 atabout the time that the piston B delivers its blow to the workingimplement.

With the valve thus reversed pressure fluid will flow over the front endof the holding surface 00 through the passage into the front end of thecylinder to actuate the piston B rearwardly. During this admission ofpressure fluid to the front end of the cylinder the pressure fluid willact against the holding surface as to hold the valve rearwardly.

After the piston B overruns the kicker passage If pressure fluid willflow through said kicker passage into the rearward end of the enlargedportion 0 to act against the actuating surface for throwing the valve (Zto its initial position. \Vhen this movement of the valve cl occurs theexhaust passage 0 will be uncovered by the flange g and the pressurefluid will escape from the front end of the cylinder through the inletpassage and the exhaust passage 0 into the enlarged portion 0 of thevalve chamber. From this point the pressure fluid may readily escape tothe atmosphere through the exhaust port p. The portion of the pressurefluid utilized for actuating the valve may of course return to thecylinder to be exhausted through the passages j and 0 along with thepressure fluid utilized for actuating the piston. However, after thevent u is uncovered pressure fluid ill also escape to the atmospherethrough said vent.

I claim:

in a fluid actuated rock drill, the combination of a cylinder andpiston, a valve chest having a valve chamber comprising an enlargedintermediate portion and reduced end portions, anexhaust port leadingfrom the intermediate portion to the atmosphere, inlet passages leadingfrom the reduced end portions to the ends of the cylinder, exhaustpassages leading from the inlet passages at the ends of the cylinder tothe enlarged intermediate portion of the valve chamber, a hollow valvein the valve chamber constantly exposed interiorly to live pressurefluid and extending slida-bly with its ends into the re duced portionsof the valve chamber, a pair of flanges on the valve slidable in theenlarged portion to control the outlet openings of the exhaust passages,actuating surfaces on the outer ends of the flanges, crossed kickerpassages leading from the intermediate portion of the cylinder to theends of the enlarged portion for conveying pressure fluid to act againstthe actuating surfaces for actuating the valve, vent ports in the valvechest spaced from the ends of the enlarged portion and adapted to becontrolled by the flanges, and holding surfaces on the ends of the valveexposed to pressure fluid flowing to the cylinder for holding the valvein thrown position.

In testimony whereof I have signed this specification.

WILLIAM A. SMITH, JR.

